by acceleration in the less developed areas. Furthermore, the advanced countries that experienced a postwar baby boom are likely to undergo a rise in birth rate during the coming years as an echo-effect of the first boom, and their population growth rates may, therefore, also increase.
DENSITY AND DEVELOPING NATIONS
Density as such is not an indicator of overpopulation. The density o population per unit of total land area in most less developed countries of Asi is less than the density in western Europe and Japan, whereas the density i the large countries of Africa and Latin America is about the same as that such "empty" countries as the United States and the Soviet Union. Exce for Taiwan and Egypt, which are exceptionally crowded, the density i cultivated land in all less developed countries is about the same as in weste Europe. Most of the countries of Africa and Latin America contain large an of arable but uncultivated land, but in Asia most land that could be cultiva has already been put under the plow. Modern high-yielding agricultural te nology and fertility limitation must be introduced and expanded in tl1 Asian countries if diets are to be improved or even if all people are to be in the future. (See Table 2.)
From 45 percent to 90 percent of the populations of the poor com live in rural areas, but the rate of growth of cities in these countries ex their overall rate of population growth. For example, between 195( 1960, in twenty-four countries with per capita incomes of less than $2' year, cities of more than 100,000 inhabitants grew 60 percent more r than the total population. The average rate of growth of these large citi over 4 percent per year; they were doubling in population every 17 yeai excess growth of cities was due to migration from the countryside, in u result of the diminishing size of farms and the increasing difficu making a living in rural areas. Although living conditions for many migi the cities are appallingly bad, they are probably better, from several pi view, than in the villages.
DESIRED AND ACTUAL NUMBERS OK CHILDREN
Sample surveys of both urban and rural people in less developed c
show that a high proportion of couples having four or more living ch:
not want any more. The best current data strongly suggest thai
.....~ <tw> number of live births exceeds by one or two children tVv